<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>JS体验</title>
</head>
<body>

<script>
    // JS代码 打印5次Hello World
    for(var i=0;i<5;i++ ){
        document.write("helloworld"+"<br/>");
        
    }

</script>
<input type="button" value="前进" onclick="history.forward()"/><br/>
<input type="button" value="后退" onclick="history.back()"/><br/>
</body>
</html>